Regrettable Engine strip down !!!! I think

I measured the original valve in the lathe, with a dial gauge. But not measuring the stem ! i only measured the widest part of the valve head. This was about 1mm out in the circumference measurement. Then decided to buy a new valve. Saying that before the strip. #6 was making 135psi

That explains the oddity. Measuring on the circumference may not be a true reading since that surface was not a machined surface to begin with. I use a " Last word indicator" and indicate off of the sealing face of the valve.